[llvm] Fix an assert failure with a funclet in a swifttailcc function. (PR #78806)

[Hiroshi Yamauchi via llvm-commits]

hjyamauchi wrote:

PTAL @compnerd. The previous reversion turned out to be incorrect. I think the latest revision should work. I believe that SwiftTailCC should be treated as Win64 as seen in [the X86 equivalent](https://github.com/llvm/llvm-project/blob/db4ea21dfde307f4fc873a6fe56791cd7ae3f0a1/llvm/lib/Target/X86/X86Subtarget.h#L357) and the fixed object size needs to be adjusted to account for the tail call reserved stack for SwiftTailCC.

https://github.com/llvm/llvm-project/pull/78806